1. Field of the Invention
This invention relates in general to air conditioning devices and more particularly to an air cooling apparatus which operates on the principles of evaporative cooling and heat exchange.
2. Description of the Prior Art
Devices for cooling air by the evaporation principle have been used for many years with the most successful use of such devices occurring in relatively dry climates for both commercial and residential applications.
The most common evaporative cooler in use today includes a cabinet in which an air moving device, usually in the form of a motor driven centrifugal blower, is mounted for drawing relatively hot and dry ambient air into the cabinet through wettable pads mounted in the sides thereof. As the incoming ambient air moves through the wet pads, it is cooled by evaporation and the air moving device delivers the cooled air to an outlet that is normally mounted in the bottom of the cabinet. A sump located in the bottom of the cooler cabinet is provided with a float controlled shutoff valve which maintains a predetermined water level in the sump, and a motor driven pump is employed to supply water under pressure from the sump into a distribution plumbing network mounted in the top of the cabinet. The water is delivered to the tops of the pads by the plumbing network and flows under the influence of gravity through the pads with the unevaporated water returning to the sump for recirculation.
Although evaporative coolers of the above described type have long been recognized as low cost and relatively efficient mechanisms, their effective use is inherently limited to times when the humidity is low in that their air cooling capability diminishes as the humidity in the atmosphere increases.
Due to the lessening of air cooling effectiveness in times of relatively high humidity, many existing evaporative coolers were replaced with refrigeration units when such units were developed in suitable packages and became available at reasonable initial investment costs, and new construction went almost exclusively to the use of refrigeration units. This trend away from evaporative coolers to refrigeration units in comparatively dry regions started about 20 to 25 years ago and was very well accepted by the consuming public as long as energy was plentiful and relatively inexpensive.
Now, however, with energy in relatively short supply and becoming more expensive every day, many are looking once again to the evaporative cooler as a source of energy conservation and economic relief. The trend today is not a complete reversal of the movement away from evaporative coolers, but is toward a compatable union of evaporative coolers and refrigeration units.
To establish a compatable union, many consumers are placing both an evaporative cooler and a refrigeration unit in communication with a common air delivery ducting network and are using the evaporative cooler when climatic conditions allow the effective use thereof and operate the more costly and energy consuming refrigeration unit only when the evaporative cooler becomes ineffective. This has proven to be successful as far as the reduction of energy and the lowering of operating costs are concerned. However, the search continues for further improvements.
To the best of my knowledge, nothing has been devised, or suggested to supplement the operation of evaporative coolers to enable them to satisfactorily cool air in spite of climatic conditions with the object being to completely replace the more expensive refrigeration units or at least substantially reduce the use time in the above described combination air conditioning system.